Daily Zohar 4388
Holy Zohar text. Daily Zohar -4388

Hebrew translation:

159. מִשּׁוּם כָּךְ, כְּשֶׁהִתְבַּשֵּׂר אַבְרָהָם, הַדַּרְגָּה הַזּוֹ הָיְתָה אוֹמֶרֶת כְּמוֹ שֶׁנִּתְבָּאֵר שֶׁכָּתוּב שׁוֹב אָשׁוּב אֵלֶיךָ כָּעֵת חַיָּה. וַיֹּאמֶר – לֹא כָּתוּב מִי הָיָה, וְזֶהוּ פֶּתַח הָאֹהֶל. וְעַל זֶה וְשָׂרָה שֹׁמַעַת דַּרְגָּה זוֹ שֶׁהָיְתָה מְדַבֶּרֶת עִמּוֹ מַה שֶּׁלֹּא הָיְתָה שׁוֹמַעַת מִקֹּדֶם לָזֶה, שֶׁכָּתוּב וְשָׂרָה שֹׁמַעַת פֶּתַח הָאֹהֶל, שֶׁהָיְתָה מְבַשֶּׂרֶת וְאוֹמֶרֶת שׁוֹב אָשׁוּב אֵלֶיךָ כָּעֵת חַיָּה וְהִנֵּה בֵן לְשָׂרָה אִשְׁתְּךָ.
160. בֹּא רְאֵה כַּמָּה חֲבִיבוּת הַקָּדוֹשׁ בָּרוּךְ הוּא לְאַבְרָהָם, שֶׁהֲרֵי לֹא יָצָא מִמֶּנּוּ יִצְחָק עַד שֶׁנִּמּוֹל. אַחַר שֶׁנִּמּוֹל הִתְבַּשֵּׂר עַל יִצְחָק, מִשּׁוּם שֶׁאָז הוּא זֶרַע קָדוֹשׁ, וְטֶרֶם שֶׁנִּמּוֹל אֵינוֹ זֶרַע קָדוֹשׁ, וְאָז הוּא כְּמוֹ שֶׁכָּתוּב (בראשית א) אֲשֶׁר זַרְעוֹ בוֹ לְמִינֵהוּ.


Zohar Vayera
Continued from previous DZ
when Abraham was told that they would have a child, Isaac, the level that is called “tent door (opening),” which is Malchut, said,
Genesis 18:10
“וַיֹּאמֶר שׁוֹב אָשׁוּב אֵלֶיךָ כָּעֵת חַיָּה וְהִנֵּה בֵן לְשָׂרָה אִשְׁתֶּךָ וְשָׂרָה שֹׁמַעַת פֶּתַח הָאֹהֶל וְהוּא אַחֲרָיו.”
“And He said, “I will certainly return to you according to the time of life, and behold, Sarah, your wife shall have a son.” (Sarah was listening in the tent door, which was behind him.)”
It says, “And he said,” but not who said that to Abraham. The word “וַיֹּאמֶר” “And he said” without reference alludes to the Shechina.
Sarah heard the “tent door” speak to Abraham about what she would not have heard before; as it is written, “Sarah was listening to the tent door,” announcing that she will have a child.

The Holy One, Blessed be He, loved Abraham and waited for him to circumcise himself before telling him about having Isaac. After circumcision, Isaac could come from a holy seed, and before he is circumcised, he is not a sacred seed. Then he is as it is written;
“ אֲשֶׁר זַרְעוֹ בוֹ לְמִינֵהוּ ” “with seed according to their kinds” (Genesis 1:12). The seed follows the origin.

When planning to have a child, the couple should be at their utmost purity because it affects the outcome. Hashem waited for Abraham to purify himself with circumcision and enter the bond of the covenant before opening the channel for him to have a child.
We ask Hashem for many things but need to remember to build a proper and pure vessel to receive the Light that we ask for. This is an important spiritual principle to follow.